The present invention relates to a light scanning system and more particularly to a light scanning system for use in a laser beam printer.
Light scanning systems are disclosed in U.S. Pat. No. 3,750,189 and Japanese Patent Laid-open Nos. 55-15131 and 58-93021. The light scanning systems disclosed in the above mentioned references have an optical system for deflecting a light beam, the angle of deflection normally being .+-.20.degree.-.+-.25.degree. or thereabout. In a system in which the angle of deflection is smaller, the space occupied by the optical system becomes larger in order that a larger deflecting distance (the scanning distance by the light beam) is obtained. If the deflecting angle of the light beam is selected to be as large as .+-.40.degree.-.+-.50.degree., the optical system can be made smaller. Generally, however, according as a larger deflecting angle is selected, field curvature or scan nonlinearity of the image formed by the optical system becomes larger.
In the light scanning system disclosed in U.S. Pat. No. 3,750,189, for example, a cylindrical lens is disposed between the rotating mirror and image plane so that the field curvature in the scan plane is corrected but the field curvature in the cross-scan plane is increased.